leetcode打カードシリーズ-2

leetcode打カードシリーズ-2
両数の和

def twosum(nums,target):
    for i in range(0,len(nums)):
        for j in range(i+1,len(nums)):
            if (nums[i]+nums[j]) == target:
                return([i,j])
            

時間複雑度O(N 2)

def twosum(nums,target):
    dic = {}
    for i in range(len(nums)):
        j = target - nums[i]
        if j in dic.keys():
            return [dic[j],i]
        dic[nums[i]] = i

時間複雑度O(N)